Conventional packages, such as the TO220 package, typically include a heat sink or other support on which the component or chip is mounted and a plurality of leads electrically connected to the heatsink. The component or chip, heat sink and one end of the leads are encapsulated in a molded body, usually formed of a resin material. One end of the heat sink is provided with legs that connect to a tie bar extending from the package. The legs and tie bar are used to support the components during encapsulation of the package. When the package has been formed, this extension piece can be removed from the package by pulling the tie bar with material encapsulating this which together form a tab. This ruptures the metal material to separate the tie bar from the completed package.
A problem with the known devices formed in this way is that when the legs are ruptured when the tie bar is broken from the formed package, the ends of the legs will be exposed within small holes extending from the end of the package. If the devices are used with high voltage applications, arcing can result from this exposed metal. Accordingly, the existence of the exposed metal means that the devices are limited to low voltage applications.